I love the background, very interesting
The inner design feels too large. In adition it is not overly interesting.
The problem with the composition is that the eye is drawn off the piece, down to the lower right. THis is not so good.
The great thing about Da Vinci's work is that its very personal, with the small notes and text. If you made the design maybe 60% of its size and added some other small illustrations it would greatly increase the piece's appeal.
I think you are developing a great way to make this kind of art, but your 'abstract' designs are letting you down.